Rancidity retardant



Patented Aug. '2, 1932 UNITED, STATES PATENT OFFICE GODFREY EDWARD SOHARFF, OF STEVENSTON, SCOTLAND, ASSIGNOR TO E. I. DU PONT DE NEMOURS & COMPANY, OF WILMINGTON, DELAWARE, A CORPORATION DELA- WARE No Drawing. Application filed October 2'8, 1928, Serial No. 315,348, and in Great Britain November This invention relates to a method for the prevention of rancidity of vegetable oils used as an ingredient of plastic coating compositions.

Such material suffers the defect that the vegetable oil tends to become acid, and thus there is a normal development of a rancid odor and subsequent deterioration in quality of the coated fabric.

Heretofore, a method for the prevention of rancidity in vegetable oils used as ingredients of plastic compositions for coating fabric, paper or the like has been developed which consists in the addition to the oil and other 16 ingredients of a small quantity of a metallic sulphide, particularly a sulphide'of the second group in wet analysis, for example, antimony, arsenic, zinc or lead sulphide.

The object of the present invention is to 2 provide an improved or modified method for the purposes referred to above,

The invention comprises the addition to the oil and other ingredients making up a plastic coating composition tity of magnesium oxide.

. The invention includes processes for the prevention of rancidity in vegetable oils used as ingredients of plastic compositions for coating fabric, paper, and the.like substantially as hereinafter described, and in coated fabrics or the like prepared with the aid of spch treated oils. y

In carrying the invention into-effect in one form by way of example, I introduce 2%,

calculated on the weight of vegetable oil, of

finely ground magnesium oxide into the flexible coating composition during the preparation of the latter before it is applied to the fabric. p I have found that by the addition of magnesium oxide rancidity of the oil contained in the composition, as evidenced by the development of a rancid odor, is retarded for a much longer period than is the case with compositions from which the magnesium oxide has been omitted One of the advantages of the use of magnesiumoxide is the fact that it is white and 59 is, therefore, a particularly desirable maof a smallquanterial to introduce into coating compositions of white or light shades.

It is to be understood that the term magnesium oxide includes commercial material which may contain c'ertain quantities of hydrated magnesium hydroxides and carbonates, as well as mixtures thereof;

As many apparently widely different em bodiments of this invention may be made without departing from the spirit and scope 09 thereof, it is to be understood that I do not limit myself to the specific embodiments thereof except as defined in the appended claims.

v I claim -1. The method of preventing rancidity in a vegetable oil which comprises adding thereto at least 2%, based on the weight of said oil, of finely ground magnesium oxide,

2. A coating composition containing a 1'0 vegetable oil and at least 2%, based onthe weight of said 'oil, of finely ground mag nesium oxide.

In testimorlig whereof, I alfix my si ature. GODFR Y EDWARD SC 

